Preinsulated electrical terminal

ABSTRACT

An electrical terminal having a contact portion and a ferrule portion, the ferrule portion being surrounded by an insulating covering, the contact portion being surrounded by an open-ended insulating housing, the insulating covering of the ferrule portion serving to restrain withdrawal of the terminal from the housing.

United States Patet lnventor Jean Gorjat Barcelona, Spain Appl. No. 18,437 Filed Mar. 11, 1970 Patented Dec. 21, 1971 Assignee AMP Incorporated Harrisburg, Pa. Priority Jan. 8, 1970 Spain 146500 PREINSULATED ELECTRICAL TERMINAL 1 Claim, 5 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 2,393,083 1/1946 Wisegarver 339/213 2,925,578 2/1960 Huffet al 339/213 3,349,365 10/1967 Dozier 339/254 FOREIGN PATENTS 743,256 9/1966 Canada 339/258 S Primary Examiner-Marvin A. Champion Assistant Examiner-Robert A. l-llafer Att0rneysCurtis, Morris and Safford, William J. Keating,

William ll-lintze, Frederick W. Rating, John R. Hopkins, Adrian J. La Rue and Jay L. Seitchik U.S.Cl 3391217 B,

339/207 R, 339/213 T, 339/223 R ABSTRACT: An electrical terrninal having a contact portion Int. Cl ..1I0lv13/50, and a ferrule portion, the ferrule portion being surrounded by l-lOlr 9/08 an insulating covering, the contact portion being surrounded Field of Search 339/206, by an open-ended insulating housing, the insulating covering 2 256 258 P. 276 of the ferrule portion serving to restrain withdrawal of the ter- T minal from the housing.

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PATENIEU m2! Ian SHEET 1 OF 2 PREINSULATED ELECTRICAL TERMINAL This invention relates to an electrical terminal. An electrical terminal may comprise a contact portion, for example a receptacle, for mating with a contact element, e.g., an electrically conductive tab, and a crimping ferrule portion extending from one end of the contact portion in substantial alignment with the contact portion, for crimping to a wire to make electrically conductive contact with the wire and to secure the wire to the terminal. In use, a series of such terminals may be required to be mated with contact elements which are closely adjacent one another, for example, contact elements extending from an insulating housing of an electrical connector, for example a feedthrough terminal block. Under such circumstances, the terminals should be fully insulated to restrain electrical flashover between adjacent terminals and also possible short circuiting, for example by reason of a metal object being accidentally introduced between a pair of adjacent terminals.

According to the invention, in an electrical terminal comprising a contact portion for mating with a contact element, and a crimping ferrule portion extending from one end of the contact portion substantially in alignment with the contact portion, the contact portion and the ferrule portion being surrounded by an insulating covering, the contact portion is sur rounded by an open-ended insulating housing into which the terminal has been inserted to an extent limited by engagement of the housing with a shoulder of the terminal, an insulating sleeve surrounding and secure to the ferrule portion engaging the housing to restrain withdrawal of the terminal from the housing.

The housing may have an internally choked portion for cooperation with the shoulder, to limit the insertion of the terminal into the housing. Where the contact portion is a receptacle for a flat tab which is joined to the ferrule portion by a transition portion which tapers towards the ferrule portion, the housing conveniently comprises a substantially rectangular portion adjoining a further portion having sidewalls which converge in a direction away from the substantially rectangular portion. These sidewalls serve to engage the transition portion of the ferrule to limit the insertion of the contact portion into the housing.

The sleeve is conveniently force-fitted to the ferrule portion.

The invention will now be described by way of example with reference to the drawings, in which:

FIG. I is a perspective view of an electrical terminal in association with an electrically conductive tab to be mated with the terminal, the tab being shown in fragmentary form;

FIG. 2 is a perspective view of an insulating sleeve assembly;

FIG. 3 is a perspective view of an insulating housing;

FIG. 4 is a longitudinal sectional view showing the sleeve assembly and the housing assembled to the terminal; and

FIG. 5 is a plan view of FIG. 4 but showing the sleeve assembly crimped to a wire.

As shown in FIG. 1, a terminal 1 comprises a receptacle portion 2 connected by a tapered transition portion 3 to a crimping ferrule portion 4 comprising a circular section cylindrical tube extending in axial alignment with the receptacle portion 2. The portion 2 has a base 6 and sidewalls 8 extending from opposite edges of the base 6 and being smoothly curled over towards the base 6 so that an electrically conductive tab 10 can be inserted into the receptacle portion 2 in the direction of the arrow A so as to be gripped between the free longitudinal edges 7 of the sidewalls 8 and the base 6.

As shown in FIG. 2, an insulating sle-eve assembly l2, comprises a circular section cylindrical copper sleeve 12 of slightly smaller internal diameter than the external diameter of the ferrule portion 4 and which is contained within a synthetic plastics sleeve M, for example of polyvinyl chloride, which has been secured about the sleeve I2 by a clinching operation, as indicated at 16.

As shown in FIG. 3, an open-ended synthetic plastics housing 18, made for example of polyethylene, has a substantially rectangular portion 20 and an internally choked portion 22 having sidewalls 23 which converge in a direction away from the portion 22.

For the purpose of insulating the terminal I, the terminal I is inserted into the housing I8 by sliding the housing 18, with its portion 20 foremost, over the terminal I in the direction of the arrow B in FIG. I until the receptacle portion 2 of the terminal l is completely covered by the portion 20 of the housing 18, the convergent sidewalls 23 of the portion 22 engaging the tapered transition portion 3 of the terminal I, as indicated in broken lines in FIG. 5, thus limiting the insertion of the terminal into the housing 18. The sleeve assembly 12 is then force-fitted over the ferrule portion 4 of the terminal, in the direction of the arrow B in FIG. ll, so that the leading, i.e., lefthand (as seen in FIG. 2), end of the assembly 12 engages the adjacent end of the portion 22 of the housing 18, so that the terminal cannot be withdrawn from the housing 18. The terminal I is thus surrounded by an insulating covering formed by the sleeve assembly 12 and housing 18, as shown in FIGS. 4 and 5.

In use, an end of an insulated wire 24, this end having been previously stripped of insulation to bare the electrically conductive core 26 of the wire 24, is inserted into the ferrule portion 4 and crimping pressure is applied to the ferrule portion 4 through the sleeve assembly 13 to deform the ferrule portion 4 into secure engagement with the bared portion of the core 26. The assembly 12 is shown in its crimped state in FIG. 5.

The present invention is claimed in accordance with the following:

1. An electrical terminal comprising a contact portion for mating with a contact element, and a crimping ferrule portion extending from one end of the contact portion substantially in alignment with the contact portion, the contact portion and the ferrule portion being surrounded by an insulating covering comprising a generally rectangular section open-ended insulating housing surrounding the contact portion of the terminal and into which the terminal has been inserted to an extent limited by the engagement of a shoulder of the terminal with an internally choked portion of the housing, a circular cross section metal sleeve force-fitted over the crimping ferrule portion in a generally coaxial relationship thereto, and an insulating sleeve closely surrounding the metal sleeve in generally coaxial relationship and interference fitted to the metal sleeve, the insulating sleeve engaging the housing to restrain withdrawal of the terminal from the housing. 

1. An electrical terminal comprising a contact portion for mating with a contact element, and a crimping ferrule portion extending from one end of the contact portion substantially in alignment with the contact portion, the contact portion and the ferrule portion being surrounded by an insulating covering comprising a generally rectangular section open-ended insulating housing surrounding the contact portion of the terminal and into which the terminal has been inserted to an extent limited by the engagement of a shoulder of the terminal with an internally choked portion of the housing, a circular cross section metal sleeve force-fitted over the crimping ferrule portion in a generally coaxial relationship thereto, and an insulating sleeve closely surrounding the metal sleeve in generally coaxial relationship and interference fitted to the metal sleeve, the insulating sleeve engaging the housing to restrain withdrawal of the terminal from the housing. 